Yes, PLATTER is a Scrabble word!

Letter values in Scrabble US: P 3, L 1, A 1, T 1, T 1, E 1, R 1.

Is it a valid word?

PLATTER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a large shallow dish used for serving food
sound recording consisting of a disk with a continuous groove; used to reproduce music by rotating while a phonograph needle tracks in the groove

Also: phonograph record, phonograph recording.